The Surprising Truth About Cavities! If you think your child is too young to need a dentist, you're wrong -- her teeth are at risk long before she's tasted her first piece of candy. <~~another reason why I don't feed my kid crap... and while he brushes his teeth in the morning and at night... *I* go in and brush them again after him since he's only 4. He also had his first dentist appointment at 1. My son's insurance told my ex-husband that he didn't need to go until he was 4. Incorrect!